forget or remember

After Mikan and Zao were taken away, everyone was forgotten, and Mikan became another person because of Zao's words. What is going on?And what is Mikan's true identity? ┃ Search keywords: Protagonist: Kan, Sakura Ice Dew, Hinata Zao┃ Supporting roles: Jia, Imai Hotaru, Toda Yu, Persona